脂肪酶在功能化磁性纳米材料表面吸附取向调控的机理研究

The technology of lipase immobilization plays a significant role in the field of grease refining. The catalytic property of immobilized lipase can be dramatically enhanced by controlling the orientation of lipase with its catalytic site orients toward the reactants. One particularly useful and important group of support is the magnetic nanomaterial. It can be easily recovered due to its strong magnetic moments. Recently, there were few researches which focused on the orientation controlling of lipase adsorption, and the adsorption mechanism and the interaction between the lipase and functionalized magnetic nanomaterials were still unclear. In this work, the adsorption orientation of lipase on different functionalized magnetic surfaces will be studied by a combination of multiscale molecular simulations and quartz crystal microbalance. The influence of surface chemistry, surface morphology, inorganic coatings and solution conditions will be discussed. One of the purposes of this work is to illustrate the mechanisms of lipase adsorption on functionalized magnetic nanomaterials under different conditions and to find out the most suitable condition for lipase immobilization with the catalytic site being accessible to the reactants. The simulation results will provide a theoretical support for the design and development of new nanomaterials for the lipase immobilization.

脂肪酶固定化技术在油脂化学品加工领域具有重要的工业价值，实现脂肪酶的特定取向吸附能显著提高其催化活性。磁性纳米粒子因其独特的磁学性能、易于回收等优势，成为脂肪酶固定化材料的热门选择之一。目前，调控脂肪酶以催化效率最优的取向在磁性纳米材料表面定向吸附的关键因素尚在探索阶段。针对这一科学问题，本项目拟以脂肪酶-磁性纳米材料界面体系作为研究对象，系统地研究材料表面物化性质（表面极性、带电性质等）、功能化磁性纳米粒子（外层无机修饰材料及纳米粒子曲率等）、周围溶液环境（脂肪酶浓度、离子强度和溶剂类型等）三大因素对脂肪酶吸附取向的调控机理。通过多尺度分子模拟与石英晶体微天平技术相结合的方法归纳出具有高定向吸附、高催化效率的脂肪酶固定化材料的共性规律，为新型脂肪酶固定化材料的设计与开发提供理论指导。

开展脂肪酶在功能化材料表面吸附取向的基础研究对生物工业以及能源开发等应用领域中的新技术研发起到至关重要的作用。其中，关键的基础科学前沿问题是酶在材料表面的吸附取向及构象变化。本项目运用多尺度分子模拟的方法研究了酶在功能化材料表面定向吸附的微观机理。研究结果表明酶的电偶极矢量、材料表面带电性质以及溶液环境等因素是调控酶吸附取向及构象的关键。酶的电偶极矢量对酶的吸附取向起定向作用；材料表面带电性质是控制酶催化效率的主要开关；材料表面带电密度及溶液环境能够用于调整酶的吸附稳定性。针对该项目的研究，已经在Nanoscale, ACS Sustainable Chemistry & Engineering, Journal of Membrane Science, the Journal of Physical Chemistry C, Current Opinion in Colloid & Interface Science, Langmuir等期刊发表SCI论文12篇。本项目的研究成果能够为新型脂肪酶固定化磁性纳米材料的制备提供可靠的理论支撑，并为其他酶固定化材料的设计开发提供指导。